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Old 04-12-2008, 05:30 AM
Senior Member
Join Date: Mar 2006
Location: Northern Lower Michigan
Posts: 2,547
Default RE: Converting Oil Furnace to Gas

CJS - 4/10/2008 3:11 AM

The oil furnace is pushing 15 years old and after shelling out
$600 - $700 per fill up this winter (about every 5 weeks), I'm
considering replacing it with a natural gas boiler. I already
have gas service into the house. It's a hot water baseboard
heating system. The local gas Co. (National Grid) will give you
the furnace if they do the installation, but I haven't had them
in to quote the job yet. Anybody ever done this before? Anything
to look out for or suggestions would be appreciated.

Lot's of things to consider here. Each fuel has it's advantages and disadvantages.

With oil you can still shop around for a supplier but with gas you are locked in to the gas company and who knows what the future will bring for NG? Although there is historically less maintenance with gas, that may not be the case in the future. The reason is that up til now natural gas has always been a stable fuel as far as BTU/therm content is concerned. This is definitely changing and will become more pronounced as our country has to import more LNG. This will be especially true on the East Coast where current pipeline capacity is barely able to meet demand. These imported fuels will be blended with existing supplies and variation in the fuel will lead to combustion problems such as sooting, CO and poor performance. There are boilers available that can compensate for variation but rest assured, the ones the gas company is offering are not that type. In my location ( state depression) natural gas is less than half the cost of oil or propane. It's a no brainer here. BTW....make sure the gas company shows the delivered cost of the fuel. Lot's of them tell you only the cost for the gas then when you get the bill all the other stuff is on there.

As to boilers.......With a hot water system we have found that we can typically reduce a customers fuel consumption by 35-50% when using a high efficiency modulating/condensing (M/C) boiler with an intelligent control package. For a good, better, best range check out the Munchkin, Triangle Tube Prestige and the Viessmann Vitodens. All of these will chop a fuel bill by a minimum of 25% and the best of them will do well over that. They are all capable of providing variable water temperature based on how cold it is outside and will also change the firing rate based on the actual system load based on demand. Cruise control for your boiler. As to the afore mentioned problem of variations in gas, the Viessmann has a burner that is capable of dealing with it.

For a good comparison of actual cost/million BTU's the website has a fuel cost comparison that works really well. ( amazing,something from the government that works) It allows you to input local fuel costs and efficiency of the appliance.

Whoever does your install should do a heat loss calc on you house to see what is actually needed. We find that the vast majority of boilers and furnaces are oversized by a large amount. This is a huge fuel waster. Any heating guy that shows up and gives you a price without doing a heat loss calc should be shown the door. If you want to have some ammunition in your pocket to see if the guy knows what he's talking about. you can go to and download a heat loss program you can run yourself.

Hope this helps. The times they are a changin' in the energy business.

s_ebels is offline